The present invention relates to valve assemblies for dispensing beverages post-mixed from a liquid concentrate and a diluent such as beverages mixed from sugar syrups and carbonated water, fruit juices and water or pulpy citrus concentrate and water. Valves of this type include separate valves for controlling the flow of diluent from a pressurized source and the flow of concentrate, usually from a gravity flow supply tank. In the more common applications, the diluent and concentrate are chilled and maintained at a temperature of approximately 40-45 degrees Farenheit (4-10 degrees Centigrade). Precise control of the mixing of the diluent concentrate in the proper proportions is required in order to maintain the flavor and consistency of the mixed beverage. Examples of this type of valve are found in the well known soda fountain dispensers employed for automatic post-mixing and dispensing of carbonated beverages.
Where chilled beverages are to be dispensed, it has been found very difficult to maintain the beverage concentrate and diluent at the desired temperature in the valving chamber immediately adjacent the dispensing valves such that the temperature of the first drink dispensed after a dwell period is the same as the temperature of later dispensed drinks after diluent and concentrate had been flowing through the valving chamber for some period of time.
Where a single valve assembly is desired to be used for dispensing a number of different mixed beverages, as for example, carbonated sugar syrup beverages and beverages comprising a mixture of citrus concentrate and water, the mixing structure of the valve must be altered to accommodate the different mixing ratios required for the different drinks. In order to provide for this capability, previously known valves have required disassembly of the valve body structure for changing of the orifices for controlling the flow of diluent concentrate.
Another valve design previously employed for effecting mixing of concentrate and diluent has employed an adjustable diffuser for controlling the amount of carbonization of the diluent and such a device is described in U.S. Pat. No. 3,727,844 issued to Robert S. Bencic. Where it is desired to dispense post-mix beverages by mixing flavored sugar syrup concentrate and carbonated water diluent, the syrup concentrate may be supplied from either a pressurized source or from a gravity flow storage tank. However, where it is desired to dispense a beverage mixed from pulpy citrus concentrate and water as a diluent, it has been found necessary to provide a pressurization to the supply of pulpy concentrate to effect flow of the pulp through the mixing valves. Problems have arisen in this regard where a relatively small orifice is needed to control the flow of pulpy concentrate for mixing in the correct proportion with the diluent. The pulpy concentrate tends to accumulate and block the metering orifice. Furthermore, where only a low gravity head is available for pulpy concentrate flow, a relatively large flow passage through the concentrate valving chamber is required to effect proper flow. A larger flow passage requires a larger valve seat, which in turn, for a given valve closing spring, results in reduced surface pressure on the valve seating surface. Increasing the spring bias force necessitates more force from the power means and requires either a larger solenoid coil or more current flow and thus greater power consumption. Thus, it has long been desired to find a way to provide a post-mix dispensing valve capable of dispensing either flavored sugar or citrus pulp concentrate mixed beverages from a low pressure head source and with a low force/power actuator.